"What we're seeing is that they're turning to wine as their preferred alcoholic beverage of choice, and they are interested in more approachable, slightly sweet, aromatic wines like moscato," she said.

Another factor was the introduction of lesser-known varieties, such as moscato, a sweeter white wine that has seen a big boost in popularity in the U.S. Gallo sees the appeal of that wine as dovetailing with another trend, the rise of wine-lovers among the millennial generation people born after 1980.